Greg_S S2 Coupe 20+ years going strong

[Greg_S]

anyone?

[newsh]

Worth swapping the 2 sensors round I'd say, no idea if it would start if it was wrong though.. You've washed the ISV out with WD40 I take it?

[Greg_S]

Im going to take the ISV off again and give it another clean with some WD40 and IPA.

Took a couple of videos today of the running





What do you reckon it could be that is causing it? Only does it when warm.

Quite often wont even start up properly.

[Greg_S]

Might get a few minutes to work on the S2 over the weekend, going to start with cleaning the ISV out. But reckon the MFTS might be the next item to purchase even though it isnt generating a fault code the issue is defintely temperature related.

Also trying to decide which injectors to go for when doing turbo upgrade, EV14's look like a good choice. Currently run RS2 injectors but wondered how much of a map tweak would be required with existing setup?

Also got a quote for bit of body work, gonna get another soon and hopefully have her in to have new bumper fitted, wheel arches and bonnet stone chips sorted and blown in.

[andy10v]

Have you tried to see how it runs with the MFTS unplugged?

I thought ABYs paid more attention the the temp sensor on the back of the head?

[driftin jo]

yes, as far as I know the ECU uses the one on the back of the head for fueling/timing etc as mentioned above, it uses a signal from the MTFS for over temp to turn off boost control.

What temp do you get in vag com when warm ?

[Greg_S]

I had completely forgotten about the sensor on back of the head. Will try unplugging this so see if it make a difference to the starting, also found the RS2 manual online so will check the measure groups with vag com and see if they are in tolerance against that too.

[Greg_S]

Been out tinkering for a while longer now, tried disconneting the rear temp sensor on head to no avail. Also cleaned ISV and tested the MAF output. MAF is giving 1.4v from pins 1 and 3 when ignition on and about 2.6v on idle.

Also checked resistance between pins 1 and 2 and all looks ok.

I did find that when the engine was running and did keep idling that disconnecting the MAF bought the idle revs down to about 800rpm, but reconnecting typically they rose to around 1300rpm so may need to buzz out between MAF connector and ECU connector too.

Although even with it connected or disconnected I am still having trouble starting. Engine turns over but doesnt quite fire all of the time, what is best way to test the cam position sensor output incase this is operating intermittently?

Checked the TPS also and the idle switch is operating correctly, I havent yet checked the resistance range, but this wasnt replaced that long ago. I will try adjusting its position incase ECU is picking up wrong throttle angle.

[Greg_S]

Also chekced that G28 is connected to Grey connector on bulkhead connector so that looks ok. With the engine hot the engine wont start unless you actuate the throttle, then the engine starts but will not idle. Ive checked G40 cam postion sensor as much as I can. Between pins 1 and 3 with ignition on is 5v as is between 1 and 2.
I havent got a scope so cant easily test it activating every other rotation.

Also found one of fuel supply lines weeping a little fuel so just nipped that up and resolved that too.

Any ideas what else to try?

[europeanme]

i might be a little thick but have you changed your throttle cable?

[mcandmar]

Unusual symptoms Greg, dont really have anything to suggest that you haven't tried. Is it possible you have a dodgy MAF or connection?

[Greg_S]

Was having a few thoughts on this last night after having a chat to my dad. Going to try a leak test on all of the boost hoses and see if I have a leak anywhere. Also going to take the injectors out and see about getting them cleaned incase there is a blockage.

[Greg_S]

i might be a little thick but have you changed your throttle cable?

I havent changed it at moment, its on the list to do at some point, but for the most part I was operating the throttle cam by hand while I was testing.

[emil]

hello

a friend has the same problem
still do not know where the problem

[Greg_S]

Well ive spent 1 1/2 hours out there again this afternoon and found a few minor problems after the rebuild. Found I hadnt tightened the jubiliee clip on the N75 on connection to the MAF to turbo hose. But the more important one was the pipe from intercooler to the water injection wasnt fitted properly so that is now in and would have definetly been causing a boost leak.

However the problem is now consistent. It struggles to start when cold or hot. Also seem to be loosing a little bit of PAS fluid and coolant, found the coolant was leaking from the bottom rad thermostat which I have nipped up and I think the PAS may be leaking from small rubber pipe on bottom of reservoir to to metal pipe across the rad. Ive cleaned them right up so will be able to see if I can track that down when I am out next.

Also had the undertray off and a good visual inspection underneath for any issue, tried to do a boost leak test. But I dont have a compressor at home and a foot pump just doesnt cut the mustard for that.

Decided to remove the injectors in the end as engine almost starts but doesnt run smoothly so wondering if could be a ******ed injector or blockage and with higher revs it is less noticeable so going to get them sent off to be cleaned and flow checked.

Before removing the injectors turning engine over it would hardly fire, of if it did would get to about 400rpm and die immediately. Tried a couple more times and was idling very lumpy at about 600rpm. Adding a little throttle about 1400rpm then the engine was trying to maintain revs and was hunting between 1300 and 1800 rpm.

I pulled the fault codes again too and got the usual G28 and 00513, and on one occasion 65535 which could be a bad earth so I will be checking the main earth strap on the engine and resistance back to the ECU incase the behaviour is because of some funny ground loops going on.

Can anyone recommend a good place to have the injectors ultrasonically cleaned near Bedford that inst too unreasonable, had a look around on web and going rate seems to be between £12.50 and £15 per injector.